Disk memory device, disk memory device defect detecting method, and program recording medium

ABSTRACT

A disk memory device is provided that measures a time for reading or writing a prescribed amount of data with an access time measurement part, compares access time data with a previously set limit time with an access time defect determining part, and, when the access time data exceeds the limit time, determines that a corresponding area on a disk memory ( 4 ) is defective, and enters the area into a defect list so that the corresponding area is not used. Thereby, when the disk memory device is used for recording/reproducing AV data, data access is performed within a prescribed time, so that videos are reproduced without interruption or data is recorded without lack of frame.

TECHNICAL FIELD

The present invention relates to a disk memory device for recording orreading data on/from a disk memory medium such as a magnetic disk or amagneto-optical disc and, more particularly, to a method for determininga defect of the disk memory device, which includes a determination of adefect position on the disk memory medium.

BACKGROUND ART

In a disk memory device, in a case where a deficiency due to a flaw orthe like exists on a disk memory medium on which data are recorded, whenthe data written in a sector including the deficiency portion is read, aread error sometimes occurs. Further, when the deficiency portion existsin a servo signal part on the disk memory medium, which part haspreviously been recorded for positioning a head structure, thedeficiency portion adversely affects the accuracy of the head structurepositioning and, thus, a position of a target sector from/into whichdata is to be read or written can not be specified. In this case, a readerror or a write error for the target sector sometimes occurs.

Accordingly, since the sector on the disk memory medium where an erroroccurs in writing or reading is unreliable, when the disk memory devicereads or writes data, generally, such sector is skipped or substitutedby a spare sector, so that the sector where the error occurs is notused.

Conventionally, in order to perform the substitution process or the likefor the error portion on the disk memory medium, a process of checking adefect position on the disk memory medium is performed by conducting atest of writing and reading data into/from all sectors on the diskmemory medium to previously judge the existence of a read or writeerror.

In the conventional process of checking the defect position on the diskmemory medium, even when writing/reading fails once in thewriting/reading test, it is not judged that the sector has an error ifdata can be normally written or read after several times of recoveryprocess.

For example, in the disk memory device, when a deficiency due to a flawor the like exists on the disk memory medium on which data are to berecorded, and a read error occurs in reading the data which are writtenin a sector including the deficiency portion, the disk memory devicegenerally attempts error correction by a data correction process such asECC correction, or performs an error recovery process of attemptingseveral times of data reading from the sector where the read erroroccurs until the data are normally read. Also, when the deficiencyportion exists in the servo signal part and adversely affects theaccuracy of the head structure positioning and, thus, the position ofthe target sector from/into which the data are to be read or writtencannot be specified, the disk memory device usually performs a headstructure positioning recovery process of attempting several times ofposition specifying process until the position of the target sector isspecified.

When the conventional disk memory device can normally read or write datafrom/into the sector on the disk memory medium by executing theabove-described recovery process, it is not judged that the sector hasan error even when the data reading or writing requires a longer timethan usual.

However, when the above-described disk memory device is employed forrecording/reproducing AV data, it is required to read or write requireddata from/on the disk memory medium of the disk memory device within aprescribed time so as to reproduce video without interruption or recorddata without lack of frames. Accordingly, when the disk memory device isemployed for recording/reproducing AV data, it is required to assurethat the reading or writing process is finished within the prescribedtime, and in addition, that the stored data are normally read. In theconventional sector defect determining method, it is impossible todetermine a position which requires an access time longer than theprescribed time, as defective, and thus when data are recorded orreproduced in/from the position, there occurs lack of data at therecording or lack of frame at the reproduction.

The present invention is made to solve the above-described conventionalproblems and has for its object to provide a disk memory device which isable to reproduce videos without interruption or record pictures withoutlack of frame when the disk memory device is employed forrecording/reproducing AV data, a disk memory device defect determiningmethod, and a recording medium storing a program for processing thedetermining method by a computer.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda disk memory device comprising: an access time measurement part formeasuring a time for reading or writing a prescribed amount of data; alimit time setting part for setting limit times for reading and writingthe prescribed amount of data; an access time defect determining partfor comparing the measured access time with the set limit time todetermine a defect in an accessed area according to whether the accesstime is longer than the limit time or not; and a defect entry part forentering a position of an area which is determined as defective by theaccess time defect determining part, into a defect list, as a defectivearea position.

Therefore, it is possible that a data storage position which cannot beaccessed within a prescribed time is detected and the detected defectivesector or defective sector block is skipped or substituted by a sparesector so as not to be used, whereby when the disk memory device isemployed for recording/reproducing AV data, the disk memory device canread or write required data from/on a disk memory medium within theprescribed time so as to reproduce video without interruption or torecord data without lack of frame.

According to a second aspect of the present invention, there is provideda disk memory device defect determining method comprising: measuring atime for reading or writing a prescribed amount of data; previouslysetting limit times for reading and writing the prescribed amount ofdata; and comparing the measured access time with the set limit time todetermine a defect in an accessed area according to whether the accesstime is longer than the limit time or not.

Therefore, a data storage position which cannot be accessed within aprescribed time is detected and, thus, the detected defective sector ordefective sector block can be skipped or substituted by a spare sectorso as not to be used.

According to a third aspect of the present invention, there is provideda program recording medium in which a program for making a computerexecute a defect determining process of a disk memory device isrecorded, the defect determining process comprising: measuring a timefor reading or writing a prescribed amount of data; previously settinglimit times for reading and writing the prescribed amount of data; andcomparing the measured access time with the set limit time to determinea defect in an accessed area according to whether the access time islonger than the limit time or not.

Therefore, a data storage position which cannot be accessed within aprescribed time is detected by a computer process, and the detecteddefective sector or defective sector block can be skipped or substitutedby a spare sector so as not to be used.

According to a fourth aspect of the present invention, there is provideda disk memory device comprising: an access time measurement part formeasuring a time for reading or writing a prescribed amount of data; anaccess time data storage part for storing the measured access time; areference time data storage part for storing data of an access timewhich is measured for the whole access area at manufacture of the diskmemory device, as reference time data; and a defect determining part forcomparing the access time data with the reference time data to determinea defect of the disk memory device.

Therefore, performance degradation after manufacture of the disk memorydevice can be judged.

According to a fifth aspect of the present invention, there is provideda disk memory device defect determining method comprising: measuring atime for reading or writing a prescribed amount of data and storing themeasured access time as access time data; storing data of an access timewhich is measured for the whole access area at manufacture of a diskmemory device, as reference time data; and comparing the stored accesstime data with the stored reference time data to determine a defect ofthe disk memory device.

Therefore, performance degradation after manufacture of the disk memorydevice can be judged.

According to a sixth aspect of the present invention, there is provideda program recording medium in which a program for making a computerexecute a defect determining process of a disk memory device isrecorded, the defect determining process comprising: measuring a timefor reading or writing a prescribed amount of data and storing themeasured access time as access time data; storing data of an access timewhich is measured for the whole access area at manufacture of the diskmemory device, as reference time data; and comparing the stored accesstime data with the stored reference time data to determine a defect ofthe disk memory device.

Therefore, performance degradation after manufacture of the disk memorydevice can be judged by a computer process.

According to a seventh aspect of the present invention, there isprovided a disk memory device comprising: an access time measurementpart for measuring a time for reading or writing a prescribed amount ofdata; an access time data storage part for storing the measured accesstime; a reference time data storage part for storing data of an accesstime which is measured for the whole access area at manufacture of thedisk memory device, as reference time data; a defect determining partfor comparing the access time data with the reference time data todetermine a defect of the disk memory device; and a defect notificationpart for notifying a host device for controlling the disk memory deviceor a display part for displaying data, of the defect of the disk memorydevice when it is judged that the disk memory device is defective fromthe result of the determination by the defect determining part.

Therefore, when the defect determining part of the disk memory devicejudges that the disk memory device is defective, it is possible to takea measure such as saving data recorded on a disk memory medium in thedisk memory device into another recording medium or exchanging the diskmemory device.

According to an eighth aspect of the present invention, there isprovided a disk memory device defect determining method comprising:measuring a time for reading or writing a prescribed amount of data andstoring the measured access time as access time data; storing data of anaccess time which is measured for the whole access area at manufactureof a disk memory device, as reference time data; comparing the storedaccess time data with the stored reference time data to determine adefect of the disk memory device; and notifying a host device forcontrolling the disk memory device or a display part for displayingdata, of the defect of the disk memory device when it is determined thatthe disk memory device is defective in the defect determination.

Therefore, it is possible to take a measure such as saving data in thedisk memory device into another recording medium or exchanging the diskmemory device.

According to a ninth aspect of the present invention, there is provideda program recording medium in which a program for making a computerexecute a defect determining process of a disk memory device isrecorded, the defect determining process comprising: measuring a timefor reading or writing a prescribed amount of data and storing themeasured access time as access time data; storing data of an access timewhich is measured for the whole access area at manufacture of the diskmemory device, as reference time data; comparing the stored access timedata with the stored reference time data to determine a defect of thedisk memory device; and notifying a host device for controlling the diskmemory device or a display part for displaying data, of the defect ofthe disk memory device when it is determined that the disk memory deviceis defective in the defect determination.

Therefore, it is possible to take a measure such as saving data in thedisk memory device into another recording medium or exchanging the diskmemory device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a construction of adisk memory device according to a first embodiment of the presentinvention.

FIG. 2 is a flowchart illustrating an example of a process of the diskmemory device according to the first embodiment of the invention.

FIG. 3 is a block diagram illustrating an example of a construction of adisk memory device according to a second embodiment of the presentinvention.

FIG. 4 is a flowchart illustrating an example of a process atmanufacture of the disk memory device according to the second embodimentof the invention.

FIG. 5 is a flowchart illustrating an example of a process at use of thedisk memory device according to the second embodiment of the invention.

FIG. 6 is a diagram illustrating an example of structures of referencetime data and access time data according to the second embodiment of theinvention.

FIG. 7 is a diagram illustrating an example of a structure of accesstime frequency distribution data according to the second embodiment ofthe invention.

FIG. 8 is a block diagram illustrating an example of a constitution of adisk memory device according to a third embodiment of the presentinvention.

FIG. 9 is a flowchart illustrating an example of a process of the diskmemory device according to the third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

Hereinafter, a first embodiment of the present invention will bedescribed with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram as an example illustrating a construction of adisk memory device according to the first embodiment of the presentinvention. In the drawing, a host device 1 outputs a test startinstruction to a disk memory device 100 to instruct the same to conducta test of an area on a disk memory 4 which is a recording area in thedisk memory device 100.

The disk memory device 100 according to the first embodiment of thepresent invention comprises an access instruction issuance part 2, adisk memory I/F part 3, a disk memory 4, a buffer part 5, a host I/Fpart 6, an end status detection part 7, an access time measurement part8, an access time defect determining part 9, a limit time setting part10, a defect entry part 11, and a defect list 12.

When the access instruction issuance part 2 receives the test startinstruction from the host device 1 through the host I/F part 6, theaccess instruction issuance part 2 instructs the disk memory I/F part 3to sequentially read or write data from/into a prescribed size of areaon the disk memory 4, as well as instructs the access time measurementpart 8 to start, measuring an access time. When the disk memory I/F part3 finishes accessing the prescribed size of area on the disk memory 4,the access instruction issuance part 2 instructs the disk memory I/Fpart 3 and the access time measurement part 8 to repeat theabove-described process for a next prescribed size of area, so that anentire specified area on the disk memory 4 is accessed while shiftingthe same by the prescribed size.

The disk memory I/F part 3 controls data transfer to/from the diskmemory 4, and reads data from the disk memory 4 to store the data in thebuffer part 5, or writes the data stored in the buffer part 5 into thedisk memory 4.

The end status detection part 7 detects an end status of the access fromthe disk memory I/F part 3 to the disk memory 4 and, when an erroroccurs, notifies the defect entry part 11 of a position of an area onthe disk memory 4 where the error occurs. On the other hand, when noerror occurs, the end status detection part 7 instructs the access timemeasurement part 8 to finish measuring the access time.

The access time measurement part 8 measures, as an access time, a periodof time from when it receives the access time measurement startinstruction from the access instruction issuance part 2 to when itreceives the access time measurement finish instruction from the endstatus detection part 7.

The limit time setting part 10 sets limit times for reading and writingprescribed amount of data from the host device 1 through the host I/Fpart 6, and stores the set limit times. The limit time setting part 10may be an input device which can set a value, such as a dip switch, anda memory.

The access time defect determining part 9 compares the access timemeasured by the access time measurement part 8 with the limit time setby the limit time setting part 10, to check whether the access time islonger than the limit time or not and, when the access time is longerthan the limit time, notifies the defect entry part 11 of a position ofan accessed area on the disk memory 4 as a defective position.

The defect entry part 11 enters the position of the defective area intothe defect list 12 on the basis of the notifications of the defectivearea detection from the end status detection part 7 and the access timedefect determining part 9.

Next, processing to be performed by the disk memory device 100 accordingto the first embodiment of the present invention will be described withreference to a flowchart shown in FIG. 2. FIG. 2 is a flowchartillustrating a series of processes to be performed by the disk memorydevice according to the first embodiment of the present invention.

Initially, the access instruction issuance part 2 obtains the test startinstruction, as well as start and end positions of the specified area onthe disk memory 4 where a test is to be conducted, an access method(only writing, only reading, writing and reading), the size of an areafor one access as an access area size, and a limit time for the accessto the access area size, from the host device 1 through the host I/Fpart 6 (step S1).

Then, the obtained access limit time is stored in the limit time settingpart 10, and the other variables are stored in the access instructionissuance part 2. Further, the various kinds of variables obtained fromthe host device 1, i.e., the start and end positions of the specifiedarea on the disk memory 4 where the test is to be conducted, the accessmethod (only writing, only reading, writing and reading), the size of anarea for one access as an access area size, and the access limit timefor the access area size, can be fixedly stored in the disk memorydevice 100. In this case, the host device 1 has only to issue the teststart instruction.

The access instruction issuance part 2 which has received the variouskinds of variables decides an access area on the disk memory 4 so thatthe specified area on the disk memory 4 where the test is to beconducted is sequentially accessed from the start position, for everyaccess area size (step S2).

Then, the access instruction issuance part 2 issues the accessinstruction which is specified in the access method obtained in step S1to the disk memory through the disk memory I/F part 3, for the accessarea decided in step S2 (step S3), as well as issues the access timemeasurement start instruction to the access time measurement part 8 toinstruct the same to start measuring an access time. The access timemeasurement part 8 starts measuring the access time (step S4).

The end status detection part 7 waits for a notification of an end ofdata transfer between the disk memory I/F part 3 and the disk memory 4,from the disk memory I/F part 3 (step S5).

When the end status detection part 7 receives the notification of thedata transfer end from the disk memory I/F part 3 in step S5, the endstatus detection part 7 detects a data transfer error which has occurredbetween the disk memory I/F part 3 and the disk memory 4, or an errorwhich has occurred in the disk memory 4, on the basis of a process endstatus which is contents of the process end notification received fromthe disk memory I/F part 3 (step S6).

When the process end status detection part 7 detects the occurrence ofthe error in step S6, the defect entry part 11 enters the access areawhere the error has occurred into the defect list 12 (step S9).

On the other hand, when the process end status detection part 7 does notdetect occurrence of the error in step S6, the end status detection part7 instructs the access time measurement part 8 to finish measuring theaccess time, thereby finishing the measurement of the access time (stepS7).

The access time defect determining part 9 compares the access timemeasured by the access time measurement part 8 in step S7 with the limittime stored in the limit time setting part 10 (step S8).

As the result of the comparison in step S8, when the access time islonger than the limit time, the defect entry part 11 enters this accessarea into the defect list 12 (step S9).

Then, the access instruction issuance part 2 confirms whether the entirespecified area on the disk memory 4 has been accessed or not, and whenthe access is not completed, the processes from step S2 to step S9 arerepeated.

As described above, according to the first embodiment, the disk memorydevice 100 is provided with the access time measurement part 8 formeasuring a time for reading or writing a prescribed amount of data onthe disk memory 4, the limit time setting part 10 for setting limittimes for reading and writing the prescribed amount of data, and theaccess time defect determining part 9 which compares the measured accesstime with the set limit time to determine a defect in the accessed areaaccording to whether the access time is longer than the limit time ornot. Therefore, a data storage position on the disk memory 4 whichcannot be accessed within the prescribed time can be detected, and adefective sector or a defective sector block including the data storageposition can be skipped or substituted by a spare sector so that thedefective sector or the sector block is not used. Thus, when the diskmemory device is employed for recording/reproducing AV data, the diskmemory device 100 can read or write required data from/into the diskmemory 4 within the prescribed time so as to reproduce video withoutinterruption or to record the data without lack of frame.

In the disk memory device 100 of the first embodiment, the determinationof a defect in an accessed area on the disk memory 4 may be realized bysoftware.

Embodiment 2

Next, a second embodiment of the present invention will be describedwith reference to FIGS. 3 to 7.

According to the second embodiment, when a disk memory device isemployed for recording/reproducing AV data to reproduce video withoutinterruption or to record the data without lack of frame, the diskmemory device judges not only the existence of defective area on a diskmemory 4 so that the defective area is skipped or substituted, but alsothe life of the disk memory device used for recording/reproducing the AVdata on the basis of each piece of information on an access time atmanufacture of the disk memory device so as to prevent degradation inon-track performance and increase in retrial process, which are causedby degradation in performance of the disk memory device.

FIG. 3 is a block diagram as an example illustrating a construction ofthe disk memory device according to the second embodiment of the presentinvention. In the drawing, a host device 1 outputs a test startinstruction to a disk memory device 100 a to instruct the same toconduct a test of an area on the disk memory 4. Further, the host device1 outputs an access instruction to the disk memory device 100 a toinstruct the same to read data recorded in the disk memory 4 or writedata therein.

The disk memory device 100 a according to the second embodiment of thepresent invention comprises an access instruction issuance part 2, adisk memory I/F part 3, the disk memory 4, a buffer part 5, a host I/Fpart 6, an end status detection part 7, an access time measurement part8, a reference time data storage part 13, an access time data storagepart 14, and a disk memory defect determining part 15.

Initially, at manufacture of the disk memory device 100 a, when theaccess instruction issuance part 2 receives the test start instructionfrom the host device 1 through the host I/F part 6, the accessinstruction issuance part 2 instructs the disk memory I/F part 3 tosequentially read or write data from/into an area on the disk memory 4by the prescribed size of area, as well as instructs the access timemeasurement part 8 to start measuring an access time. When theabove-described accessing process is finished, the process is repeatedto access a next prescribed size of area on the disk memory 4, so thatan entire specified area on the disk memory 4 is accessed while shiftingthe specified area by the prescribed size.

The disk memory I/F part 3 controls data transfer to/from the diskmemory 4, and reads data from the disk memory 4 to store in the bufferpart 5 or writes the data stored in the buffer part 5 into the diskmemory 4.

The end status detection part 7 detects an end status of the access fromthe disk memory I/F part 3 to the disk memory 4, and instructs theaccess time measurement part 8 to finish measuring the access time.

The access time measurement part 8 measures, as an access time, a periodof time from when it receives the access time measurement startinstruction from the access instruction issuance part 2 to when itreceives the access time measurement finish instruction from the endstatus detection part 7, and updates reference time data 18 on thereference time data storage part 13. The reference time data 18 storedin the reference time data storage part 13 will be described later.

Next, at use of the disk memory 4, when the access instruction issuancepart 2 receives the access instruction for the prescribed amount of dataarea from the host device 1 through the host I/F part 6, the accessinstruction issuance part 2 instructs the disk memory I/F part 3 to aread or write data from/into a corresponding area on the disk memory 4,as well as instructs the access time measurement part 8 to startmeasuring the access time.

The disk memory I/F part 3 controls data transfer to/from the diskmemory 4, and reads data from the disk memory 4 to store the data in thebuffer part 5, or writes the data stored in the buffer part 5 into thedisk memory 4.

The host I/F part 6 controls transfer of a command and data to/from thehost device 1, and outputs the data stored in the buffer part 5 to thehost device 1 or stores data outputted from the host device 1 into thebuffer part 5.

The end status detection part 7 detects the end status of the accessfrom the disk memory I/F part 3 to the disk memory 4, and instructs theaccess time measurement part 8 to finish measuring the access time.

The access time measurement part 8 measures, as an access time, a periodof time from when it receives the access time measurement startinstruction from the access instruction issuance part 2 to when itreceives the access time measurement finish instruction from the endstatus detection part 7, and updates access time data 19 on the accesstime data storage part 14. The access time data 19 stored in the accesstime data storage part 14 will be described later.

The disk memory defect determining part 15 checks whether or not theaccess time measured by the access time measurement part 8 is longerthan a prescribed time by which an area on the disk memory 4 is judgedas defective. Further, every time data access occurs by a prescribednumber of times, the disk memory defect determining part 15 compares theaccess time data 19 stored in the access time data storage part 14 withthe reference time data 18 stored in the reference time data storagepart 13 to check the existence of defective area in the disk memory 4 ordegradation in performance of the whole disk memory 4.

Here, descriptions will be given of the reference time data 18 stored inthe reference time data storage part 13 and the access time data 19stored in the access time data storage part 14, with reference to FIGS.6 and 7.

The reference time data 18 and the access time data 19 have the sameformat. The reference time data 18 is created on the basis of data of anaccess time which is measured as a reference of an access time for thespecified area on the disk memory 4 when the disk memory device 100 a ismanufactured. The access time data 19 is updated by access time datathat is obtained by measuring the access time for the prescribed amountof data area on the disk memory 4 when the disk memory 4 is used.

The reference time data 18 and the access time data 19 are constitutedby write access time data 21 and read access time data 22, each beingconstituted by a maximum access time 23 or 27, access time frequencydistribution data 24 or 28 which is divided into classes according tothe access time, a mode value 25 or 29 which is calculated on the basisof the access time frequency distribution data, and an arithmetic meanvalue 26 or 30. As shown in FIG. 7, the width of the class of the accesstime data frequency distribution data 24 or 28 is 5 ms, and a range from0 to 100 ms is divided into the classes, thereby measuring thefrequency. The format is decided in consideration of access performanceof the target disk memory 4.

When the maximum access time, the mode value, or the arithmetic meanvalue of the access time data 19 is larger than each data of thereference time data 18 by a prescribed value or more, it is judged thatthe performance of the disk memory 4 is degraded.

Next, a process of the disk memory device 100 a according to the secondembodiment of the present invention will be described with reference toflowcharts shown in FIGS. 4 and 5.

FIG. 4 is a flowchart illustrating a series of process at manufacture ofthe disk memory device according to the second embodiment of the presentinvention. FIG. 5 is a flowchart illustrating a series of process at useof the disk memory device according to the second embodiment of thepresent invention.

Initially, the process of the disk memory device 100 a at manufacturethereof will be described with reference to FIG. 4.

At manufacture of the disk memory device 100 a, when the accessinstruction issuance part 2 receives the test start instruction from thehost device 1 through the host I/F part 6, the access instructionissuance part 2 decides an access area so that an access test issequentially conducted for the entire data area on the disk memory 4, inascending order of addresses, by every prescribed size of area (stepS20).

Next, the access instruction issuance part 2 issues a write accessinstruction to the disk memory 4 through the disk memory I/F part 3 forthe access area on the disk memory 4 which is decided in step S20 (stepS21), as well as issues an access time measurement start instruction tothe access time measurement part 8 to instruct the same to startmeasuring an access time. Then, the access time measurement part 8starts measuring the access time (step S22).

The end status detection part 7 waits for a notification of an end ofthe data transfer between the disk memory I/F part 3 and the disk memory4, from the disk memory I/F part 3 (step S23).

In step S22, when the end status detection part 7 receives thenotification of the data transfer end from the disk memory I/F part 3,the end status detection part 7 instructs the access time measurementpart 8 to finish measuring the access time, and the access timemeasurement part 8 finishes the measurement of the access time (stepS24).

The access time measurement part 8 updates the reference time data 18 onthe reference time data storage part 13 on the basis of the measuredaccess time (step S25).

Then, the access instruction issuance part 2 confirms whether the entiredata area on the disk memory 4 is accessed, and when the access is notcompleted yet, the process from step S20 to step S25 is repeated.

After a series of process from step S20 to step S25 is finished for thewhole data area on the disk memory 4 with respect to the write access,in order to execute the same process with respect to a read access, theaccess instruction issuance part 2 receives the test start instructionfrom the host device 1 through the host I/F part 6, and decides anaccess area to sequentially conduct the access test for the whole dataarea of the disk memory 4, in ascending order of addresses, by everypredetermined size of area (step S27).

Then, the access instruction issuance part 2 issues a read accessinstruction to the disk memory 4 through the disk memory I/F part 3 forthe area decided in step S27 (step S28), as well as issues the accesstime measurement start instruction to the access time measurement part8, so that the access time measurement part 8 starts measuring theaccess time (step S29).

Then, the end status detection part 7 waits for the notification of anend of the data transfer between the disk memory I/F part 3 and the diskmemory 4, from the disk memory I/F part 3 (step S30).

When the end status detection part 7 receives the notification of thedata transfer end from the disk memory I/F part 3 in step S29, the endstatus detection part 7 instructs the access time measurement part 8 tofinish measuring the access time, and the access time measurement part 8finishes the measurement of the access time (step S31).

Then, the access time measurement part 8 updates the reference time data18 on the reference time data storage part 13 on the basis of themeasured access time (step S32).

The access instruction issuance part 2 confirms whether the whole dataarea of the disk memory 4 has been accessed or not (step S33), and whenthe access is not completed yet, the processes from step S27 to step S32are repeated.

When the access to the whole data area of the disk memory 4 is finished,the reference time data 18 relating to the access time of the diskmemory device 100 a at measurement thereof, which is created on thereference time data storage part 13, is stored in a system area on thedisk memory 4 through the disk memory I/F part 3 (step S34).

It is assumed that the reference time data 18 stored in the system areaon the disk memory 4 is read into the reference time data storage parton a RAM when power of the disk memory device 100 a is applied.

Next, the process of the disk memory device 100 a at use of the diskmemory 4 will be described with reference to FIG. 5.

Initially, at use of the disk memory, when the access instructionissuance part 2 receives the access instruction from the host device 1through the host I/F part 6, the access instruction issuance part 2checks whether the access instruction targets at a prescribed amount ofdata area (step S40).

When the access instruction does not target at the prescribed amount ofdata area in step S40, the access instruction issuance part 2 issues anaccess instruction for the corresponding area on the disk memory 4 tothe disk memory 4 through the disk memory I/F part 3 (step S41), and theprocess is finished.

On the other hand, when the access instruction targets at the prescribedamount of data area (step S40), the access instruction issuance part 2issues an access instruction for the corresponding area on the diskmemory 4 to the disk memory 4 through the disk memory I/F part 3 (stepS42), as well as issues the access time measurement start instruction tothe access time measurement part 8 to instruct the same to start themeasure of the access time. The access time measurement part 8 startsmeasuring the access time (step S43).

Then, the end status detection part 7 waits for a notification of an endof the data transfer between the disk memory I/F part 3 and the diskmemory 4, from the disk memory I/F part 3 (step S44)

When the end status detection part 7 receives the notification of thedata transfer end from the disk memory I/F part 3 in step S44, the endstatus detection part 7 instructs the access time measurement part 8 tofinish measuring the access time, and the access time measurement part 8finishes the measurement of the access time (step S45).

Then, the access time measurement part 8 updates the access time data 19on the access time data storage part 14 on the basis of the measuredaccess time (step S46).

The disk memory defect determining part 15 checks whether the accesstime measured in step S45 is longer than a prescribed time by which theaccess area is judged as defective, and when the access time is longerthan the prescribed time, the disk memory defect determining part 15updates the number of defective area detections 20 on the access timedata storage part 14 (step S47).

Further, the disk memory defect determining part 15 measures the numberof times the access time data is acquired, and checks whether the numberof access time data acquisitions reaches a prescribed number of times ornot (step S48).

When the number of access time data acquisitions reaches the prescribednumber of times, the disk memory defect determining part 15 compares theaccess time data 19 stored in the access time data storage part 14 withthe reference time data 18 stored in the reference time data storagepart 13, and checks the existence of defective area in the disk memory 4or performance degradation of the whole disk memory 4 (step S49), andthe process is finished.

It is assumed that the access time data 19 and the number of defectivearea 20 which are stored in the access time data storage part 14 arestored in the system area on the disk memory 4 at a timing in which thedata transfer process of the disk memory device 100 a is not prevented,and the access time data 19 and the number of defective area detections20 stored in the system area on the disk memory 4 are read into thereference time data storage part 13 on the RAM when power is applied tothe disk memory device 100 a.

As described above, according to the second embodiment, the disk memorydevice 100 a is provided with the access time measurement part 8 formeasuring a time for reading or writing a prescribed amount of data, theaccess time data storage part 14 for storing the above-describedmeasured access time as the access time data 19, the reference time datastorage part 13 for storing the access time which is measured for thewhole access area at manufacture of the disk memory device, as thereference time data 18, and the disk memory defect determining part 15for comparing the access time data 19 with the reference time data 18 todetermine the existence of defective area in the disk memory 4 orperformance degradation thereof. Therefore, when the disk memory device100 a is employed for recording/reproducing AV data, the disk memorydevice 100 a can read or write required data from/into the disk memory 4within a prescribed time so as to reproduce video without interruptionor to record data without lack of frame. Further, performancedegradation of the disk memory 4 after manufacture of the disk memorydevice can be judged, whereby degradation in on-track performance orincrease in retrial process, which are caused by degradation inperformance of the disk memory 4, can be prevented.

In the disk memory device 100 a of the second embodiment, thedetermination of a defect in an accessed area on the disk memory 4 maybe realized by software.

Embodiment 3

Next, a third embodiment of the present invention will be described withreference to FIGS. 8 and 9.

According to the third embodiment, a disk memory device judgesdegradation in performance of a disk memory after manufacture of thedisk memory device and, further, issues a warning to a host device or auser when the disk memory is judged as defective.

FIG. 8 is a block diagram as an example illustrating a construction ofthe disk memory device according to the third embodiment of the presentinvention. In the drawing, a host device 1 outputs a test startinstruction to a disk memory device 100 b to instruct the same toconduct a test of an area on a disk memory 4. Further, the host device 1outputs an access instruction to the disk memory device 100 b toinstruct the same to read data recorded in the disk memory 4 or to writedata therein.

The disk memory device 100 b according to the third embodiment of thepresent invention comprises an access instruction issuance part 2, adisk memory I/F part 3, the disk memory 4, a buffer part 5, a host I/Fpart 6, an end status detection part 7, an access time measurement part8, a reference time data storage part 13, an access time data storagepart 14, a disk memory defect determining part 15, a disk memory defectwarning part 16, and a display part 17.

The disk memory device 100 b according to the third embodiment of thepresent invention is different from the disk memory device 100 adescribed for the second embodiment in that the disk memory defectwarning part 16 and the display part 17 are further provided. The sameconstituents as those of the disk memory device 100 a according to thesecond embodiment, except for the disk memory defect warning part 16 andthe display part 17, operate in like manners as those of the disk memorydevice 100 a according to the second embodiment, and thus they aredenoted by the same reference numerals and descriptions thereof will beomitted.

When the disk memory defect determining part 15 detects the existence ofa defective area in the disk memory 4 or performance degradation of thewhole disk memory 4, and determines that the disk memory 4 is defective,the disk memory defect warning part 16 notifies the display part 17 ofthe determination by the disk memory defect determining part 15.Further, the disk memory defect warning part 16 notifies the host device1 of the determination through the host I/F part 6.

On the basis of the notification from the disk memory defect warningpart 16 that the disk memory 4 is defective, the display part 17displays contents of the notification on an LED, a display or the like.Not only the visual display part 17 such as an LED or a display, butalso a display part using a sound source such as a buzzer sound or avoice are possible.

Next, a process of the disk memory device 100 b according to the thirdembodiment of the present invention will be described with reference toa flowchart shown in FIG. 9.

When the disk memory defect determining part 15 detects the existence ofa defective area in the disk memory 4 or performance degradation of thewhole disk memory 4, and determines that the disk memory 4 is defective(step S50), the disk memory defect warning part 16 displays thedetermination that the disk memory 4 is defective and contents of thedefect via the display part 17 (step S51).

Then, the disk memory defect warning part 16 notifies the host device 1of the determination that the disk memory 4 is defective and thecontents of the defect through the host I/F part 6 (step S52).

As described above, according to the third embodiment, the disk memorydevice 100 b is provided with the access time measurement part 8 formeasuring a time for reading or writing a prescribed amount of data, theaccess time data storage part 14 for storing the measured access time asthe access time data 19, the reference time data storage part 13 forstoring the access time which is measured for the whole access area atmanufacture of the disk memory device, as the reference time data 18,the disk memory defect determining part 15 for comparing the access timedata 19 with the reference time data 18 to determine the existence ofdefective area in the disk memory 4 or performance degradation thereof,thereby determining a defect of the disk memory device 100 b, and thedisk memory defect warning part 16 for notifying the host device 1 orthe display part 17 of the defect of the disk memory device 100 b whenit is judged that the disk memory device 100 b is defective from theresult of the determination by the disk memory defect determining part15. Therefore, by detecting performance degradation after manufacture ofthe disk memory device and notifying the host device 1 or a user of thedegradation, it is possible to take a measure such as saving data in thedisk memory device 100 b into another recording medium, or exchangingthe disk memory device 100 b.

APPLICABILITY IN INDUSTRY

A disk memory device, a disk memory device defect determining method,and a recording medium storing a program that enables a computer toexecute the method according to the present invention are extremelyuseful for reproducing video without interruption or recording pictureswithout lack of frame when the disk memory device is employed forrecording/reproducing AV data.

1. A disk memory device comprising: an access time measurement partoperable to measure a time for reading or writing a prescribed amount ofdata; an access time data storage part operable to store the measuredaccess time; a reference time data storage part operable to store dataof an access time which is measured for each of all access areas atmanufacture of the disk memory device, as reference time data; and adefect determining part operable to compare the access time data, whichis measured for each access area at use of the disk memory device, withthe reference time data, which is measured at manufacture of the diskmemory device, to determine a defect of the disk memory device.
 2. Adisk memory device defect determining method comprising: measuring atime for reading or writing a prescribed amount of data and storing themeasured access time as access time data; storing data of an access timewhich is measured for each of all access areas at manufacture of a diskmemory device, as reference time data; and comparing the stored accesstime data, which is measured for each access area at use of the diskmemory device, with the stored reference time data, which is measured atmanufacture of the disk memory device, to determine a defect of the diskmemory device.
 3. A computer readable medium in which a program formaking a computer execute a defect determining process of a disk memorydevice is stored, wherein the defect determining process comprises:measuring a time for reading or writing a prescribed amount of data andstoring the measured access time as access time data; storing data of anaccess time which is measured for each of all access areas atmanufacture of the disk memory device, as reference time data; andcomparing the stored access time data, which is measured for each accessarea at use of the disk memory device, with the stored reference timedata, which is measured at manufacture of the disk memory device, todetermine a defect of the disk memory device.
 4. A disk memory devicecomprising: an access time measurement part operable to measure a timefor reading or writing a prescribed amount of data; an access time datastorage part operable to store the measured access time; a referencetime data storage part operable to store data of an access time which ismeasured for each of all access areas at manufacture of the disk memorydevice, as reference time data; a defect determining part operable tocompare the access time data, which is measured for each access area atuse of the disk memory device, with the reference time data, which ismeasured at manufacture of the disk memory device, to determine a defectof the disk memory device; and a defect notification part operable tonotify a host device for controlling the disk memory device or a displaypart for displaying data, of the defect of the disk memory device whenit is judged that the disk memory device is defective from the result ofthe determination by the defect determining part.
 5. A disk memorydevice defect determining method comprising: measuring a time forreading or writing a prescribed amount of data and storing the measuredaccess time as access time data; storing data of an access time which ismeasured for each of all access areas at manufacture of a disk memorydevice, as reference time data; comparing the stored access time data,which is measured for each access area at use of the disk memory device,with the stored reference time data, which is measured at manufacture ofthe disk memory device, to determine a defect of the disk memory device;and notifying a host device for controlling the disk memory device or adisplay part for displaying data, of the defect of the disk memorydevice when it is determined that the disk memory device is defective inthe defect determination.
 6. A computer readable medium in which aprogram for making a computer execute a defect determining process of adisk memory device is stored, wherein the defect determining processcomprises: measuring a time for reading or writing a prescribed amountof data and storing the measured access time as access time data;storing data of an access time which is measured for each of all accessareas at manufacture of the disk memory device, as reference time data;comparing the stored access time data, which is measured for each accessarea at use of the disk memory device, with the stored reference timedata, which is measured at manufacture of the disk memory device, todetermine a defect of the disk memory device; and notifying a hostdevice for controlling the disk memory device or a display part fordisplaying data, of the defect of the disk memory device when it isdetermined that the disk memory device is defective in the defectdetermination.